1/*
  2 * Copyright (C) 2016 ARM Limited, All Rights Reserved.
  3 * Author: Marc Zyngier <marc.zyngier@arm.com>
  4 *
  5 * This program is free software; you can redistribute it and/or modify
  6 * it under the terms of the GNU General Public License version 2 as
  7 * published by the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope that it will be useful,
 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 12 * GNU General Public License for more details.
 13 *
 14 * You should have received a copy of the GNU General Public License
 15 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 16 */
 17
 18#include <linux/bitops.h>
 19#include <linux/interrupt.h>
 20#include <linux/irqchip.h>
 21#include <linux/irqchip/chained_irq.h>
 22#include <linux/irqchip/irq-partition-percpu.h>
 23#include <linux/irqdomain.h>
 24#include <linux/seq_file.h>
 25#include <linux/slab.h>
 26
 27struct partition_desc {
 28	int				nr_parts;
 29	struct partition_affinity	*parts;
 30	struct irq_domain		*domain;
 31	struct irq_desc			*chained_desc;
 32	unsigned long			*bitmap;
 33	struct irq_domain_ops		ops;
 34};
 35
 36static bool partition_check_cpu(struct partition_desc *part,
 37				unsigned int cpu, unsigned int hwirq)
 38{
 39	return cpumask_test_cpu(cpu, &part->parts[hwirq].mask);
 40}
 41
 42static void partition_irq_mask(struct irq_data *d)
 43{
 44	struct partition_desc *part = irq_data_get_irq_chip_data(d);
 45	struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
 46	struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
 47
 48	if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
 49	    chip->irq_mask)
 50		chip->irq_mask(data);
 51}
 52
 53static void partition_irq_unmask(struct irq_data *d)
 54{
 55	struct partition_desc *part = irq_data_get_irq_chip_data(d);
 56	struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
 57	struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
 58
 59	if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
 60	    chip->irq_unmask)
 61		chip->irq_unmask(data);
 62}
 63
 64static int partition_irq_set_irqchip_state(struct irq_data *d,
 65					   enum irqchip_irq_state which,
 66					   bool val)
 67{
 68	struct partition_desc *part = irq_data_get_irq_chip_data(d);
 69	struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
 70	struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
 71
 72	if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
 73	    chip->irq_set_irqchip_state)
 74		return chip->irq_set_irqchip_state(data, which, val);
 75
 76	return -EINVAL;
 77}
 78
 79static int partition_irq_get_irqchip_state(struct irq_data *d,
 80					   enum irqchip_irq_state which,
 81					   bool *val)
 82{
 83	struct partition_desc *part = irq_data_get_irq_chip_data(d);
 84	struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
 85	struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
 86
 87	if (partition_check_cpu(part, smp_processor_id(), d->hwirq) &&
 88	    chip->irq_get_irqchip_state)
 89		return chip->irq_get_irqchip_state(data, which, val);
 90
 91	return -EINVAL;
 92}
 93
 94static int partition_irq_set_type(struct irq_data *d, unsigned int type)
 95{
 96	struct partition_desc *part = irq_data_get_irq_chip_data(d);
 97	struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
 98	struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
 99
100	if (chip->irq_set_type)
101		return chip->irq_set_type(data, type);
102
103	return -EINVAL;
104}
105
106static void partition_irq_print_chip(struct irq_data *d, struct seq_file *p)
107{
108	struct partition_desc *part = irq_data_get_irq_chip_data(d);
109	struct irq_chip *chip = irq_desc_get_chip(part->chained_desc);
110	struct irq_data *data = irq_desc_get_irq_data(part->chained_desc);
111
112	seq_printf(p, " %5s-%lu", chip->name, data->hwirq);
113}
114
115static struct irq_chip partition_irq_chip = {
116	.irq_mask		= partition_irq_mask,
117	.irq_unmask		= partition_irq_unmask,
118	.irq_set_type		= partition_irq_set_type,
119	.irq_get_irqchip_state	= partition_irq_get_irqchip_state,
120	.irq_set_irqchip_state	= partition_irq_set_irqchip_state,
121	.irq_print_chip		= partition_irq_print_chip,
122};
123
124static void partition_handle_irq(struct irq_desc *desc)
125{
126	struct partition_desc *part = irq_desc_get_handler_data(desc);
127	struct irq_chip *chip = irq_desc_get_chip(desc);
128	int cpu = smp_processor_id();
129	int hwirq;
130
131	chained_irq_enter(chip, desc);
132
133	for_each_set_bit(hwirq, part->bitmap, part->nr_parts) {
134		if (partition_check_cpu(part, cpu, hwirq))
135			break;
136	}
137
138	if (unlikely(hwirq == part->nr_parts)) {
139		handle_bad_irq(desc);
140	} else {
141		unsigned int irq;
142		irq = irq_find_mapping(part->domain, hwirq);
143		generic_handle_irq(irq);
144	}
145
146	chained_irq_exit(chip, desc);
147}
148
149static int partition_domain_alloc(struct irq_domain *domain, unsigned int virq,
150				  unsigned int nr_irqs, void *arg)
151{
152	int ret;
153	irq_hw_number_t hwirq;
154	unsigned int type;
155	struct irq_fwspec *fwspec = arg;
156	struct partition_desc *part;
157
158	BUG_ON(nr_irqs != 1);
159	ret = domain->ops->translate(domain, fwspec, &hwirq, &type);
160	if (ret)
161		return ret;
162
163	part = domain->host_data;
164
165	set_bit(hwirq, part->bitmap);
166	irq_set_chained_handler_and_data(irq_desc_get_irq(part->chained_desc),
167					 partition_handle_irq, part);
168	irq_set_percpu_devid_partition(virq, &part->parts[hwirq].mask);
169	irq_domain_set_info(domain, virq, hwirq, &partition_irq_chip, part,
170			    handle_percpu_devid_irq, NULL, NULL);
171	irq_set_status_flags(virq, IRQ_NOAUTOEN);
172
173	return 0;
174}
175
176static void partition_domain_free(struct irq_domain *domain, unsigned int virq,
177				  unsigned int nr_irqs)
178{
179	struct irq_data *d;
180
181	BUG_ON(nr_irqs != 1);
182
183	d = irq_domain_get_irq_data(domain, virq);
184	irq_set_handler(virq, NULL);
185	irq_domain_reset_irq_data(d);
186}
187
188int partition_translate_id(struct partition_desc *desc, void *partition_id)
189{
190	struct partition_affinity *part = NULL;
191	int i;
192
193	for (i = 0; i < desc->nr_parts; i++) {
194		if (desc->parts[i].partition_id == partition_id) {
195			part = &desc->parts[i];
196			break;
197		}
198	}
199
200	if (WARN_ON(!part)) {
201		pr_err("Failed to find partition\n");
202		return -EINVAL;
203	}
204
205	return i;
206}
207
208struct partition_desc *partition_create_desc(struct fwnode_handle *fwnode,
209					     struct partition_affinity *parts,
210					     int nr_parts,
211					     int chained_irq,
212					     const struct irq_domain_ops *ops)
213{
214	struct partition_desc *desc;
215	struct irq_domain *d;
216
217	BUG_ON(!ops->select || !ops->translate);
218
219	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
220	if (!desc)
221		return NULL;
222
223	desc->ops = *ops;
224	desc->ops.free = partition_domain_free;
225	desc->ops.alloc = partition_domain_alloc;
226
227	d = irq_domain_create_linear(fwnode, nr_parts, &desc->ops, desc);
228	if (!d)
229		goto out;
230	desc->domain = d;
231
232	desc->bitmap = kzalloc(sizeof(long) * BITS_TO_LONGS(nr_parts),
233			       GFP_KERNEL);
234	if (WARN_ON(!desc->bitmap))
235		goto out;
236
237	desc->chained_desc = irq_to_desc(chained_irq);
238	desc->nr_parts = nr_parts;
239	desc->parts = parts;
240
241	return desc;
242out:
243	if (d)
244		irq_domain_remove(d);
245	kfree(desc);
246
247	return NULL;
248}
249
250struct irq_domain *partition_get_domain(struct partition_desc *dsc)
251{
252	if (dsc)
253		return dsc->domain;
254
255	return NULL;
256}